1. Field of the Invention
The present invention relates to an internal combustion engine with a balancer wherein confirmation of positioning in meshing between a driving gear wheel and a driven gear wheel of a balancer mechanism can be carried out easily.
2. Description of Related Art
In a conventional internal combustion engine, for example, where a crankshaft is oriented in a vehicle widthwise direction (leftward and rightward direction) when the conventional internal combustion engine is mounted on a vehicle, if a balancer mechanism having a driving gear wheel is disposed between left and right crank journal walls, then the meshing region between the driving gear wheel and a driven gear wheel for balancer driving is hidden by a pair of wall sections formed from the crank journal walls. Consequently, it is difficult to confirm alignment of “positioning marks” for adjusting the timings of the gear wheels (predetermined mutual phase).
As a countermeasure against the difficulty, for example, Japanese Patent No. 3440573 discloses an apparatus wherein a cutaway portion is provided on a crank web so that, when the balancer mechanism is assembled to the crankcase, the positioning marks in the meshing region of the driving gear wheel and the driven gear wheel can be confirmed from the opposite side of the crankcase.
However, since the internal combustion engine of Japanese Patent No. 3440573 is structured such that the crankcase is composed of two left and right parts, the meshing region of the gear wheels can be viewed directly from the opposite side of the crankcase to confirm alignment of the positioning marks. However, depending upon the form of the internal combustion engine, the meshing region may not be able to be viewed directly and alignment of the positioning marks may not be able to be readily confirmed.
Therefore, an internal combustion engine with a balancer wherein alignment of positioning marks in a meshing region of a balancer driving gear wheel and a balancer driven gear wheel of a balancer mechanism can be confirmed readily irrespective of the form of the internal combustion engine is needed.